Method for preparing trisilylamine (TSA) at ultra-low temperature

The present application claims the priority to Chinese Patent Application No. CN202111211358.5, titled “METHOD FOR PREPARING TRISILYLAMINE (TSA) AT ULTRA-LOW TEMPERATURE”, filed with China National Intellectual Property Administration (CNIPA) on Oct. 18, 2021, which is incorporated herein by reference in its entirety.

The present disclosure relates to the technical field of preparation of trisilylamine (TSA), in particular to a method for preparing TSA at an ultra-low temperature.

Trisilylamine (TSA) is a popular precursor in semiconductor processing. The growing market demand urgently seeks an efficient preparation method of the TSA in industry. Currently, the preparation method is classified according to the reaction mode of TSA, including only gas-gas reaction, gas-liquid reaction, or liquid-liquid reaction.

Most of the reactions disclosed in the existing patents are generally single solvent-based or mixed solvent-based systems, and there are also reactions of solvent-free systems, showing an easier reaction and purification process, which are detailed as follows:

Patent CN103619429A disclosed a method for preparing TSA from monochlorosilane (MCS) and ammonia. Directly using the MCS as a solvent, the ammonia is directly introduced into the liquid of MCS at −60° C. to +40° C. After the reaction, the excess MCS needs to be distilled and condensed back to a reactor. The method can be conducted batchwise or continuously and requires a large amount of energy. In practical situations, the solid ammonium chloride generated by the reaction may quickly occupy the entire reactor, resulting in the reaction being difficult to conduct completely or an extremely low yield. Moreover, the full text of the patent does not mention matters related to the yield.

Patent CN104250007A disclosed a method for preparing TSA. Using a reaction product TSA directly as a reaction solvent, a reaction mixture of TSA and MCS is provided to a reactor, followed by adding anhydrous ammonia, where the reaction mixture includes a stoichiometric excess of up to 30 wt %, or a stoichiometric excess of about 3 wt % to 5 wt % of the MCS relative to ammonia; the reaction is conducted at 20° C. to 120° C., and a large amount of the MCS needs to be distilled and condensed back to the reactor after the reaction. The method needs to consume a lot of energy, and MCS, NH, and TSA have an extremely low flash point, showing a relatively high danger coefficient under their corresponding temperature and pressure during the reaction.

To sum up, a technical problem to be solved by the present disclosure is to provide a method for preparing TSA without a solvent at an ultra-low temperature.

The present disclosure discloses a method for preparing TSA at an ultra-low temperature, and belongs to the technical field of preparation of TSA. The TSA can be prepared under a low temperature without a solvent.

The present disclosure provides a method for preparing trisilylamine (TSA) at an ultra-low temperature, including the following steps:

Further, the filtration is conducted with the metal ion-adsorption permeable membrane.

Further, a preparation method of the metal ion-adsorption permeable membrane includes the following steps:

Further, the UV lamp has a power of 500 W to 1,000 W.

Further, the UV lamp has a UV wavelength of 220 nm to 400 nm.

Further, the purification specifically includes: adding 300 parts to 500 parts by weight of the filtrate, and introducing a fore-cut fraction into a fore-cut fraction collection tank under specified temperature and pressure; collecting a TSA product into a finished product tank, conducting rectification at an atmospheric pressure, and terminating the rectification after retaining a liquid level of 4% to 7%.

Further, the specified temperature and pressure are 60° C. to 70° C. and 2 kPa to 5 kPa, respectively.

In the present disclosure, the ultra-low temperature reaction has a reaction mechanism as follows:

Under the low temperature, it is conducive to a forward progress of the reaction; it is beneficial to the stability of raw materials and products, and a decomposition rate is greatly reduced; it is beneficial for generated by-products to be precipitated with smaller particles, and a small amount of liquid remaining on the solid after filtration can be directly ignored.

Technical Innovation Points:

Detection Method:

The product purity is characterized by domestic GC; the product purity verification and impurity analysis are conducted by hydrogen nuclear magnetic resonance (HNMR) spectroscopy; the content of metal ions in the product is detected by inductively-coupled plasma mass spectrometry (ICP-MS). The test results are shown in Table 1.

The present disclosure is further described below through specific examples.

MCS gas was introduced slowly into an ultra-low temperature reaction vessel equipped with a mechanical stirrer; liquefied ammonia was added dropwise; liquefied MCS and NHwere subjected to an ultra-low temperature reaction at a molar ratio of close to 1:1.2, to generate a large amount of a ammonium chloride solid, and the solid was removed by filtration; an obtained mother liquor was reintroduced into the ultra-low temperature reaction vessel, the ammonia was added, and filtration was conducted; the process was repeated 5 times by reintroducing an newly-obtained mother liquor into the ultra-low temperature reaction vessel, adding the ammonia, and conducting filtration; the MCS was detected by on-line GC, when only a small amount of the MCS was remained, filtration was conducted with a metal ion-adsorption permeable membrane, and a resulting filtrate was introduced directly into a rectification device to conduct purification; where

A preparation method of the metal ion-adsorption permeable membrane included the following steps:

The rectification (purification) specifically included: 300 g of a crude product (filtrate) was added, and a fore-cut fraction was introduced into a fore-cut fraction collection tank under specified temperature and pressure; a TSA product was collected into a finished product tank, rectification was conducted at an atmospheric pressure, and the rectification was terminated after retaining a liquid level of about 4%; where

The TSA finally obtained in the reaction had a GC purity of 99.1% and a metal ion purity of 6N.

MCS gas was introduced slowly into an ultra-low temperature reaction vessel equipped with a mechanical stirrer; liquefied ammonia was added dropwise; liquefied MCS and NHwere subjected to an ultra-low temperature reaction at a molar ratio of close to 1:1.3, to generate a large amount of a ammonium chloride solid, and the solid was removed by filtration; an obtained mother liquor was reintroduced into the ultra-low temperature reaction vessel, the ammonia was added, and filtration was conducted; the process was repeated 5 times by reintroducing an newly-obtained mother liquor into the ultra-low temperature reaction vessel, adding the ammonia, and conducting filtration; the MCS was detected by on-line GC, when only a small amount of the MCS was remained, filtration was conducted with a metal ion-adsorption permeable membrane, and a resulting filtrate was introduced directly into a rectification device to conduct purification; where

A preparation method of the metal ion-adsorption permeable membrane included the following steps:

The rectification (purification) specifically included: 400 g of a crude product (filtrate) was added, and a fore-cut fraction was introduced into a fore-cut fraction collection tank under specified temperature and pressure; a TSA product was collected into a finished product tank, rectification was conducted at an atmospheric pressure, and the rectification was terminated after retaining a liquid level of about 5%; where

The TSA finally obtained in the reaction had a GC purity of 99.4% and a metal ion purity of 6N.

MCS gas was introduced slowly into an ultra-low temperature reaction vessel equipped with a mechanical stirrer; liquefied ammonia was added dropwise; liquefied MCS and NHwere subjected to an ultra-low temperature reaction at a molar ratio of close to 1:1.4, to generate a large amount of a ammonium chloride solid, and the solid was removed by filtration; an obtained mother liquor was reintroduced into the ultra-low temperature reaction vessel, the ammonia was added, and filtration was conducted; the process was repeated 5 times by reintroducing an newly-obtained mother liquor into the ultra-low temperature reaction vessel, adding the ammonia, and conducting filtration; the MCS was detected by on-line GC, when only a small amount of the MCS was remained, filtration was conducted with a metal ion-adsorption permeable membrane, and a resulting filtrate was introduced directly into a rectification device to conduct purification; where

A preparation method of the metal ion-adsorption permeable membrane included the following steps:

The rectification (purification) specifically included: 500 g of a crude product (filtrate) was added, and a fore-cut fraction was introduced into a fore-cut fraction collection tank under specified temperature and pressure; a TSA product was collected into a finished product tank, rectification was conducted at an atmospheric pressure, and the rectification was terminated after retaining a liquid level of about 7%; where

The TSA finally obtained in the reaction had a GC purity of 99.5% and a metal ion purity of 6N.

MCS gas was introduced slowly into an ultra-low temperature reaction vessel equipped with a mechanical stirrer; liquefied ammonia was added dropwise; liquefied MCS and NHwere subjected to an ultra-low temperature reaction at a molar ratio of close to 1:1.5, to generate a large amount of a ammonium chloride solid, and the solid was removed by filtration; an obtained mother liquor was reintroduced into the ultra-low temperature reaction vessel, the ammonia was added, and filtration was conducted; the process was repeated 5 times by reintroducing an newly-obtained mother liquor into the ultra-low temperature reaction vessel, adding the ammonia, and conducting filtration; the MCS was detected by on-line GC, when only a small amount of the MCS was remained, filtration was conducted with a metal ion-adsorption permeable membrane, and a resulting filtrate was introduced directly into a rectification device to conduct purification; where

A preparation method of the metal ion-adsorption permeable membrane included the following steps:

The rectification (purification) specifically included: 300 g of a crude product (filtrate) was added, and a fore-cut fraction was introduced into a fore-cut fraction collection tank under specified temperature and pressure; a TSA product was collected into a finished product tank, rectification was conducted at an atmospheric pressure, and the rectification was terminated after retaining a liquid level of about 4%; where

The TSA finally obtained in the reaction had a GC purity of 99.2% and a metal ion purity of 6N.

MCS gas was introduced slowly into an ultra-low temperature reaction vessel equipped with a mechanical stirrer; liquefied ammonia was added dropwise; liquefied MCS and NHwere subjected to an ultra-low temperature reaction at a molar ratio of close to 1:1.6, to generate a large amount of a ammonium chloride solid, and the solid was removed by filtration; an obtained mother liquor was reintroduced into the ultra-low temperature reaction vessel, the ammonia was added, and filtration was conducted; the process was repeated 5 times by reintroducing an newly-obtained mother liquor into the ultra-low temperature reaction vessel, adding the ammonia, and conducting filtration; the MCS was detected by on-line GC, when only a small amount of the MCS was remained, filtration was conducted with a metal ion-adsorption permeable membrane, and a resulting filtrate was introduced directly into a rectification device to conduct purification; where

A preparation method of the metal ion-adsorption permeable membrane included the following steps:

The rectification (purification) specifically included: 500 g of a crude product (filtrate) was added, and a fore-cut fraction was introduced into a fore-cut fraction collection tank under specified temperature and pressure; a TSA product was collected into a finished product tank, rectification was conducted at an atmospheric pressure, and the rectification was terminated after retaining a liquid level of about 7%; where

The TSA finally obtained in the reaction had a GC purity of 99.4% and a metal ion purity of 6N.

In this comparative example, the reaction conditions were exactly the same as those in Example 1, but membrane filtration was not conducted.

The TSA finally obtained in the reaction had a GC purity of 99.1% and a metal ion purity of 3N.

In this comparative example, the reaction conditions were exactly the same as those in Example 1, but the filtration was conducted with a polysulfone hollow fiber ultrafiltration membrane.

The TSA finally obtained in the reaction had a GC purity of 99.1% and a metal ion purity of 4N.

Table 1 Data of TSA obtained by reactions of Examples 1 to 5 and Comparative Examples 1 to 2

The above description of examples is merely provided to help illustrate the method of the present disclosure and a core idea thereof. It should be noted that several improvements and modifications may be made by persons of ordinary skill in the art without departing from the principle of the present disclosure, and these improvements and modifications should also fall within the protection scope of the present disclosure. Various amendments to these embodiments are apparent to those of professional skill in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not limited to the examples shown herein but falls within the widest scope consistent with the principles and novel features disclosed herein.